Circuit interrupter



June 1.1, 1957 R. E. FRINK CIRCUIT INTERRUPTER 3 Sheets-Sheet 1 FiledDec. 8, 1954 IIIIIIIIIIII 5. I r..

mveiwon Russell E Frnk.

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June 1l, 1957 R. E. FRINKY A Fig.2. 38 -35 4o 21 sa 13:34 le 2s 25 36443 Sheets-Sheet 2 Figs.

United States Patent l 2,795,675 CIRCUIT INTERRUPTER Russell E. Frink,Forest Hills, Pa., assigner to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application December 8,1954, Serial No. 473,991 11 Claims. (Cl. 20G-147) This invention relatesgenerally to circuit interrupters, and, more specifically, toarc-extinguishing structures for magnetic air circuit interrupters.

The general object of my invention is to provide an improved circuitinterrupter, in which improved and more elective arc-extinguishingaction takes place.

Another object is to provide an improved transfer arcextinguishing meansfor a circuit interrupter of the type having an electrically floatingblowout coil to which the current is transferred by the extinguishing ofa portion of the arc playing between two arc terminal members connectedto the ends of the blowout coil.

Still, a further object is to speed up the transfer into series circuitof the magnetic blowout coil so as to bring about more rapid andeffective operation.

A further object of my invention is to utilize the shading coil for theblowout magnet in a novel manner so as to provide one or more terminalsfor the transfer arc-extinguishing means.

Still a further object is to provide an improved longer plate structurefor the transfer arc-extinguishing means of a circuit interrupter tobring about improved performance and to minimize the possibility offlashover.

Further objects and advantages will readily become apparent, uponreading the following specification taken in conjunction with thedrawings, in which:

Figure 1 is a side elevational View, partially in vertical section, of acircuit interrupter embodying the principles of my invention, and thecontact structure being shown in the closed-circuit position;

Fig. 2 is a plan sectional view of the circuit interrupter of Fig. 1,taken along the line II-II thereof;

Fig. 3 is a vertical sectional View taken along the line III- III ofFig. 1;

Fig. 4 is a side elevational view of one of the plates utilized in thearc-extinguishing sections;

Fig. 5 is a side elevational view of one of the transferarc-extinguishing plates;

Fig. 6 is a sectional View taken substantially along the line VI-VI ofFig. 7; and

Fig. 7 is an enlarged fragmentary sectional View taken substantiallyalong the line VII- VII of Fig. 3.

Referring to the drawings, and more particularly to Fig. l thereof, thereference numeral 1 generally designates a circuit interrupter, in thisinstance being one 0f the air-break type. Although the illustratedspecific embodiment of my invention is an air-break. type of circuitinterrupter, it is to be clearly understood that certain features of myinvention may be applicable to other types of circuit interrupters, sayfor instance one of the liquid-immersed type or one operating in agaseous medium. Merely for purposes of illustration do I describe aspecific embodiment of my invention which operates in air.

Generally, the circuit interrupter 1 includes contact structure 2operable to establish an arc, which is moved upwardly into an arc-chutestructure 3, including a pair of arc-extinguishing sections 4 and 5 ofsubstantially identical construction.

As well understood by those skilled in the art, one terminal L1 of thecircuit interrupter is connected to the stationary contact 6 of mydevice, whereas the other terminal L2 of the interrupter is electricallyconnected to the movable contact 7 of the device. If desired, suitablebridging and secondary contacts may be employed ICC to relieve thestationary and movable arcing contacts 6, 7 from carrying the current inthe fully closed-circuit position shown in Fig. l.

During the opening operation, the moving arcing contact 7 moves awayfrom the stationary arcing contact 6 to establish an arc 8, as shown bythe dash line of Fig. l. This arc, generally designated by the referencecharacter it, may be considered as composed of three sections 8a, 8b and8c. The arc 8, of course, bows upwardly because of the naturalconvection current of air, which is heated by the hot arc 8, and alsobecause of the magnetic forces set up by the arc 8 which act to expandtheloop of the arc, as well understood by those skilled in the art.

Adjacent the top and central portion of the arc 8 is a pair of transferarc horns 1G, 11, between which is disposed a transfer arc-extinguishingmeans, generally designated by the reference numeral 13. The arc portion8a extends between the movable arcing contact 7 and the transfer archorn 10. The arc portion 8b extends within the transferarc'extinguishing means 13 between the transfer arc horns 10, 11. Thearc portion 8c extends between the stationary arcing contact 6 and thetransfer archorn 11.

The function of the transfer arc-extinguishing means 13 is to interruptthe arc portion 8b, and so bring into series circuit the pair ofserially related, centrally disposed blowout coils 15, 16, the locationof which is more clearly shown in Fig. 2 of the drawings. Such coils, ofcourse, have insulated windings. As mentioned, the centrally disposedblowout coils 15, 16 are connected in series circuit together, as by aconnection 17 at the top of the coils (Figs. l and 3), and the otherlower ends 18, 19 of the blowout coils 16, 15, respectively, are securedto the transfer arc horns 10, 1l, respectively, as shown more clearly inFig. 1 of the drawings.

Because of the reactance of the blowout coils 15, 16, it is diflicult toforce current to flow through them because of the countervoltage set upin the coils. The transfer arc-extinguishing means 13 is, therefore,desirable to assist in this transfer into series circuit of the blowoutcoils 15, 16 by extinguishing the arc portion 8b. Generally, thetransfer arc-extinguishing means 13 includes a plurality of spacedinsulating plates 21, the configuration of which is more clearly shownin Fig. 5 ot' the drawings. lt will be noted that each insulating plate21 has a slot 22 provided therein which tapers inwardly to one side ofthe center line 23 of the plate. rhe plates 21 are spaced laterallyapart by asbestos rope spacers 21a, as more clearly shown in Fig. 2 ofthe drawings. Adjacent plates 21 may be positioned oppositely so thatthe slots 22 are alternately on opposite sides of the center line of theplates and provide a zigzag path for the arc.

Referring to Fig. l it will 'be noted that a plurality of the plates 21are disposed between the transfer arc horns 1t), 11 and the single-turnshading coil 25. The shading coil 25 in t-urn encircles the core or yokeportion 26 magnetically interconnecting the pole plate portions 27, moreclearly shown in Fig. 2 of the drawings.

Referring more specifically to Fig. 7 of the drawings, it will be notedthat the arc portion `or section 8b moves upwardly to strike the lowerend 28 of the shading coil 25 to establish two serially related arms129, 30 which are electrically in series. These arcs'move upwardlywithin the slots 22 of the insulating transfer plates 21 to becomeextinguished.

Following extinction of the arc portion Sb within the transfer'arc-extinguishing means 13, the blowout coils 15 and 16 `are seriallyconnected into the circuit, and the energization -of these coils 15, 16sets up a magnetic flux within the magnetic ycircuit 24, which includesthe pair of side magnetic pole plates 27 and the interconatesora nectingyoke 26. Preferably, the pole plates 27 are formed of verticallyextending sheets of 'a suitable magnetic material to forma laminatedstructure, more clearly shown in Fig. 2 of the drawings. Magneticallyinterconnect-ing the side pole plates 27 is the central interconnectingcore or yoke portion 26, which is encircled by the two serially relatedblowout coils 15 and 16.

As will be obvious to those skilled in the art, the H- type of magneticcircuit 24 shown, upon the energization thereof, causes magnetic flux toow 'between the pole plates 27 in vthe manner indicated by the arrows 20in Fig. 2. This magnetic flux extending transversely between the poleplates 27 causes upward movement of the are portions Sa, 8c upwardlyinto the are-extinguishing sections 4, 5 of the arc-chute structure 3.

The left-hand end of the arc portion 8a, as viewed in Fig. l, quicklytransfers to the outer arc horn 12, the lower end of which is connected,as shown, to the movable arcing contact 7 and hence to the lowerterminal L2 of the device. Also, the right-hand end of the arc portion8c quickly transfers to the right-hand arc horn 9 of the device, whichis electrically connected to the stationary contact 6 lby the connection9a and hence to the upper terminal L1 of the interrupter.

The current path through the interrupter (as viewed in Fig. l) may thenbe traced, beginning at line L1, through connection 9a, are horn :andterminal plate 9, across the arc in right-hand main extinguishingsection 5 to the transfer arc horn or plate 11, lower end 19 of frontlblowout coil `15, through -coil 15 to the connection 17 at its upperend t-o the upper end of the rear blowout coil 16, through coil 16 toits lower end 18 connected to the arc transfer plate or horn 10, throughthe arc in main left-hand extinguishing section 4 to the arc terminalplate er horn 12 on thence to line L2.

Disposed within the arc-extinguishing sections 4, 5 are the plurality ofspaced, slotted, ceramic plates 40, the configuration of which is moreclearly shown in Fig. 4 of the drawings. As shown, each ceramic plate 40has a slot 41 provided therein, the upper closed end 42 of which isslightly off-center. The plates 40 are staggered during the assemblyoperations so as to form 1a 'horizontally disposed, zigzag arc passage43 throughout the length of the are-chute sections 4, 5 to quickly bringabout the extinction of the arc portions 8a, 8c. The plates 4t) arespaced laterally apart, as shown more clearly in Fig. 2, by sections oflasbestos rope 44 cemented between the plates 4.0 adjacent the outeredges thereof, the method being identical to that previously referred toin spacing the insulating plates 21 of the transfer arcextinguishingmeans 13 apart.

Certain features of the disclosed structure have been set out andclaimed in my pending United States patent application, filed November28, 1952, Serial No. 323,009, and issued October 30, 1956, as Patent No.2,769,065, entitled Circuit Interrupter, and assigned to `the assignee'.f the instant application. This application, in part, claims thedisposition of the serially related blowout coils 15, 16 in the plane ofthe arc-chute jacket 35 to brace the blowout coils against the magneticforces occurringl during the interruption of high-fault currents.

Proper operation of the transfer arc-extinguishing means 13 is necessaryto ensure rapid blowout-coil transfer, and it is an important object ofmy invention to provide a more effective transfer arc-extinguishingmeans 13, while at the same time providing a more compa-ct and effectivestructure. It was found that with relatively short transferarc-extinguishing plates the transfer are portion 8b extending betweenthe transfer are horns 10, 1l sometimes flashed over across the top ofsuch short transfer arc-extinguishing plates to prevent the blowoutcoils 15, 16 vbeing inserted into series circuit.

l have discovered that by making the yoke portion 26 somewhat longer andnarrower than previous constructions of this type, yet having the samecross-sectional area,

that there was adequate space on both sides of the shading coil 25 todispose the relatively long transfer arc-extinguishing plates 21. Thisis all obtained without increasing the overall size of the farc chute 3.As shown in Fig. 7, with this arrangement the transfer stack is madeofsubstantially full length plates 21 and divided into two sections 31,32 and placed in the spaces between the transfer horns 10, 11 and theshading coil 25. The transfer are 8b now divides into two sections 29,39, with the shading coil 25 forming a common terminal between them.

This change accomplishes a number of desirable -results. Whereasformerly an are t-o the shading coil shorted out the transfer stack `andresulted in unsatisfactory performance, -in the present `arrangement theare is still confined to the stack. Also, the ability to use longerplates 21 in the transfer stack permits the use of a more efficient slotshape, and the length of the plates 21 beyond the ends of the slots 22eliminates the tendency toward hashing over the top of the transferstack.

Aside from improving transfer performance, this new construction resultsin two additional distinct improvements. First, it will be seen that thetransfer arc-extinguishing means 13 is not disposed so close to thecontact structure 2 to result in adequate space for a desired initiallooping effect of the are. Thus, the are 8 is able to get away fasterfrom the contacts 2, resulting in less ionization in the region of thecontacts 2, which reduces the tendency to restrike. Secondly, bydisposing the transfer plates 21 above the fire plates 33, the latterneed not be grooved to support plates below the shading coil 25, whichwas used in constructions heretofore. The strength of the fire plates 33is, consequently, considerably improved, resulting in a strongerstructure.

To rigidly support the coils 15, 16 within the apertures 34 disposed inthe insulating arc chute jacket 35, coil washers or plates 36 ofinsulating material are employed surrounding the yoke 26 and maintainedseparated by the shading coil 25, as more clearly shown in Fig. 2.

Also, preferably an insulating spacer plate 38 is utilized between thepole plate portions 27 and the blowout coils 13, 14 for insulationpurposes.

It will be noted that there is an open space indicated at A in Fig. 7.This space may be left open, as shown, so that the initial arc portion8b may move rapidly upwardly within this space A to contact the lowerend 28 of the shading coil 25 resulting in two are portions 29, 30, theextinction of which occurs in the manner heretofore described. However,for certain applications, it may be desirable to interpose within thespace A additional insulating plates of shorter length to assist in theextinction of the are 8b, particularly during low current values and myinvention is intended to cover such a modification. For higher currentvalues, the central portion of the arc 8b would move through suchshorter plates, contacting the shading coil 25 and being extinguished inthe manner as set forth above.

From the foregoing description it will be apparent that the inventionconcerns improvements particularly adapted for circuit interrupters ofthe center-coil type. However, certain features may be applied tocircuit interrupters utilizing a magnetic circuit of substantiallyU-shape, in which a transfer arc-extinguishing means is associated withthe core of such magnet. Merely for purposes of illustration have Iillustrate-d my invention as applied to an H-shaped magnet arrangementin which a centrally disposed floating center-coil magnet is utilized.

The foregoing construction has been experimentally tested in thelaboratory, and has been found to Vgive greatly improved results overprior constructions in which relatively short transfer arc-extinguishingplates were utilized. Thus, the use of long transfer plates 21 havingmore suitable slot configuration greatly speeds up interruption of thetransfer arc 8b, thereby rapidly inserting the series blowout coils 15,16 into the circuit to quickly set up the desired magnetic field withinthe arc chute sections 4, 5 of the inteirupter 1.

Certain features of the construction are described and claimed in UnitedStates patent application led January 21, 1954, Serial No. 405,322, byRussell E. Frink and Samuel A. Bottonari, issued January 8, 1957 asPatent No. 2,777,036, and assigned to the assignee of the instantapplication.

Although I have shown and described a particular structure, it is to beclearly understood that the same was merely for the purpose ofillustration, and that changes and modifications may readily be madetherein by those skilled in the art without departing from the spiritand scope of the invention.

I claim as my invention:

1. A circuit interrupter including means for establishing an arc, amagnet structure including an elongated core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a transfer arc horn spaced away from a long side ofthe core, one terminal of one of said blowout coils being connected tosaid transfer arc horn, and a relatively long transfer arc-extinguishingstructure disposed between the transfer arc horn and the long side ofthe core to eifect extinction of -a portion of said arc.

2. A circuit interrupter including means for establishing an are, amagnet structure including an oblong core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a pair of transfer arc horns on opposite sides ofthe long sides of the core and spaced therefrom, one terminal of ablowout coil connected to each transfer arc horn, and a transferarc-extinguishing structure of insulating material disposed between thelong sides of the core and each transfer arc horn.

3. The combination in -a circuit interrupter of means for establishingan are, an H-shaped magnet structure for extinguishing the arc includinga core and a pair of pole plate portions, a shading coil about the core,one or more magnetic blowout coils encircling the core to set up amagnetic eld therein, a pair of transfer are horns on opposite sides ofthe core and spaced from the shading coil, one terminal of a blowoutcoil connected to each transfer arc horn, and transfer arc-extinguishingmeans disposed between the shading coil and each transfer arc horn.`

4. The combination in a circuit interrupter of means for establishing anarc, an H-shaped magnet structure for extinguishing the arc including acore and a pair of pole plate portions, a shading coil about the core,one or more magnetic blowout coils encircling the core to set up amagnetic field therein, a transfer arc horn disposed along one side ofthe shading coil and spaced therefrom, and one or more transferarc-extinguishing plate portions disposed between the transfer arc hornand the shading coil.

5. A circuit interrupter including means for establishing an arc, amagnet structure including an elongated core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a transfer arc horn spaced away from a long side ofthe core, one terminal of one of said blowout coils being connected tosaid transfer -arc horn, and transfer arc-extinguishing plate meansdisposed between the transfer arc horn and the core to effect extinctionof a portion of said arc.

6. The combination in a circuit interrupter of means for establishing anarc, an H-shaped magnet structure for extinguishing the arc including acore and a pair of pole plate portions, a shading coil about the core,one or more magnetic blowout coils encircling the core to set up amagnetic field therein, a pair of transfer arc horns on opposite sidesof the core and spaced from the shading coil, one terminal of |a blowoutcoil connected to each transfer arc horn, said arc contacting the pairof transfer arc horns to establish a transfer arc portion, and meansproviding two Sections of insulating arc-extinguishing plates to effectextinction of the transfer arc portion.

7. A circuit interrupter including means for establishing an arc, amagnet structure including an oblong core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a transfer arc horn spaced away from :a long sideof the core, one terminal of one of said blowout coils being connectedto said transfer arc horn, a main arc horn spaced from said transfer archorn, said arc moving into engagement with the two arc horns, and arelatively long transfer arc-extinguishing structure disposed betweenthe transfer arc horn and a long side of the core to effect extinctionof a portion of said anc.

8. A circuit interruptor including means for establishing an arc, amagnet structure including an elongated core and pole plate portions forassisting in the extinction of the arc, one or more blowout `'coilsencircling the core, a transfer `arc horn spaced away from a long sideof the core, one terminal of one of said blowout coils being connectedto said transfer a-rc horn, a main arc horn spaced from `said transferarc horn, said arc moving into engagement with the two arc horns,arc-extinguishing plate portions for effecting the extinction of the arcextending between the two arc horns, and a relatively long transferarc-extinguishing structure disposed between the transfer arc horn andthe long side of the core to effect extinction of a portion of said arc.

9. A circuit interrupter including means for establishing `an arc, amagnet structure including an oblong core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a pair of transfer arc horns on opposite sides ofthe long sides of the core and spaced therefrom, a pair of main archorns spaced :away from said pair of transfer arc horns on oppositesides thereof, said arc moving into engagement with the four a-rc horns,one terminal of a blowout coil connected to each transfer arc horn, anda transfer anc-extinguishing structure of insulating material disposedbetween the long sides of the core and each transfer arc horn.

10. A circuit interrupter including means for establishing an arc, amagnet structure including a core and pole plate portions for assistingin the extinction of the arc, one or more blowout :coils encircling thecore, a transfer arc horn positioned substantially parallel to one sideof the core, one terminal of one of said blowout coils being connectedto said transfer arc horn, and a transfer arcextinguishing structureincluding a plurality of spaced plates disposed between said transferarc horn and said one side of the core, and the spaced plates beingsubstantially parallel to said one side of the core and effectingextinction of a portion of said established are.

1l. A circuit interrupter including means for establishing an arc, an H-shaped magnet structure including a core and pole plate portions forassisting in the extinction of the arc, one or more blowout coilsencircling the core, a pair of transfer arc horns positionedsubstantially parallel to and on opposite sides of the core, oneterminal of each of said blowout coils being connected to one of saidtransfer arc horn-s, and a transfer arc-extinguishing structureincluding a plurality of spaced plates disposed between each saidtransfer arc horn and the adjacent side of the core of the H-shapedmagnet structure, and the spaced plates being substantially parallel tosaid adjacent sides of the core Iand effecting extinction of a portionof said established arc.

References Cited in the tile of this patent UNITED STATES PATENTS1,398,982 Tritle Dec. 6, 1921 1,872,387 Baker et al. Aug. 16, 19322,616,007 Dickinson et al. Oct, 28, 1952

